Various displays such as liquid crystal display, projection display and plasma display have recently been developed and put into practical use. Those displays have been utilized as apparatus for displaying an image such as PC, TV, and car navigation system as usage.
Materials protecting against reflection are usually placed on the surface of display apparatuses. For example, in the case of liquid crystal display, a protection film is attached on the surface of the display in order to avoid reflection of outside light at the surface. The protection film is thin enough, so that it possesses a superior optical transparency and the liquid crystal display can display an image in the state of minimizing the loss of back light intensity even though a protection film is placed on the surface.
In contrast to the foregoing, as for a projection display apparatus displaying an image by a projection of an image light incident from the back of a transmission type screen, an anti-reflection film is prepared on a surface of a transparent panel called front plane designed for the protection of a transmission type screen and achievement of a glossy picture quality. (Refer to Patent Document: TOKKAIHEI No. 8-265675).
An ordinary transmission type screen has a positional structure for which one screen of a lenticular lens is put on top of another screen of a fresnel lens (Refer to Patent Document: TOKKAIHEI No. 6-160982). Light diffusion fine particles composed of glass and polymeric material are mixed into the base material of the lenticular lens, and each of both surfaces of the lenticular lens is in a cylindrical shape. Striped and protrusion-shaped outside light absorption layers (Black stripes) at non-light-converging areas on the side where light enters among two surfaces of the lenticular lens are formed at a given pitch, thus, a lenticular lens is designed to prevent a decline of contrast influenced by outside light.
Incidentally, in the aforementioned lenticular lens, a part of light diffusion fine particles is generally protruded from surfaces of the cylinder-shaped region and the black stripe region. In such a structure, there is a problem presented with a decline of contrast and a whitish surface of screen caused by occurrence of irregular reflection of outside light on the surface of light emergence when irregularities are present on the surface of lenticular lens and outside light is projected on the surface of the outgoing light of lenticular lens.
Though there is a method by which a transparent panel made of glass or plastics with a lower light transmittance is placed in front of a screen in order to prevent a decline of contrast caused by outside light and a decrease of definition in picture which appears on a screen, there is a problem that a picture on the screen can not be watched easily in this case because of developing extremely images of outside light (lighting fixture, viewers, and so forth) imaged on a transparent panel extremely.
An ordinary transmission type screen has a positional structure for which one screen of a lenticular lens is put on top of another screen of a fresnel lens. When a cross-section of a fresnel lens is seen, the surface of light emergence at a fresnel lens (the surface facing a lenticular lens) has a structure wherein a plurality of fresnel lens surfaces constituting a small portion of circular arc of a concentric circle and a rising surface placed between respective fresnel lenses one after the other are formed alternately and repeatedly. When a picture light is forced to enter a fresnel lens from a projection apparatus situated on the rear side of a transmission screen, the picture light is refracted on the surface of an incidence of a fresnel lens, then, is subsequently refracted on the surface of the fresnel lens again, and emerges from the surface of light emergence in the state where it is converted into a parallel light or a converged light focused on a given point.
In the case of a picture light emerging from the surface of a fresnel lens which is the surface of light emergence, however, there is an occasion when a part of picture light is reflected on the surface of the fresnel lens, then, is trapped within a fresnel lens, and is reflected again on the surface of incidence, to be ejected finally from a rising surface of the surface of light emergence as an unwanted. At this time, ghost images are shown on a screen and also a sharp decline of contrast in picture on the screen appears.
In order to solve such a problem, there is known a technique by which a light diffusion layer or a light absorption layer is provided on rising surfaces which are the surfaces of outgoing light (Refer to Patent Documents 1 and 2). In the case of providing light diffusion layers on rising surfaces, though ghost images become invisible because of total light flux of an unwanted light passing through light diffusion layers substantially with no attenuation, contrast in picture is not particularly improved. On the contrary, in the case of preparing light absorption layers on rising surfaces, though a light absorption agent of 5–10 μm in thickness such as carbon particles, black ink, and so forth has to be coated in order to absorb an unwanted light sufficiently, there is a tendency to reduce a pitch in size (for example, 100 μm) of each surface of the fresnel lens for the fine segmentalization of a picture on a screen in recent years, a picture on a screen becomes dark because of a decline of light transmittance on the surfaces of the fresnel lens in order that the surface of the fresnel lens may be interrupted by an amount equivalent to thickness of the light absorption agent for a fresnel lens which formed the surfaces of the fresnel lens with a very fine pitch.
In such a situation, it is prevented that a picture light is reflected on the surface of a fresnel lens and emerges from rising surfaces as an unwanted light by preparing an anti-reflection film on the surface of a fresnel lens with a coating technique in the techniques described in Patent Document 3 to improve the light transmittance on the surface of a fresnel lens.    [Patent Document 1] TOKKAISHO No. 50-123448    [Patent Document 2] TOKKAISHO No. 52-143847    [Patent Document 3] TOKKAI No. 2002-169225